Try a split keyboard. For me the problem is that my arms come in at a high angle horizontally to meet at the keyboard, and my wrists try to correct. Split the keyboard and you no longer have that constraint.
That's actually a good call! I just inherited something that's not quite a split keyboard -- it's one of those "ergonomic" keyboards from a colleague who left, and it basically forces my elbows out so that I can still keep my traps relaxed & wrists straight, even when my keyboard is higher than I would typically have it.